Here is the long promised posting on V02max.
V02Max and Work Intensity
Scientists frequently use V02max measurements to equate the intensity of exercise within and between groups of subjects. They speak in terms of work being performed, for example, at a speed that elicits oxygen consumption that is 70% of a person’s V02max. By doing so they can quantify the level of effort relative to each person’s individual maximum oxygen consumption and provide a more accurate representation of the work intensity. This method is great for scientists but not so good for coaches as coaches will often not know the V02max of their athletes. Coaches prefer to refer to efforts subjectively as a percentage of maximum. To help equate the two, information from studies in which work intensity has been reported as a percentage of V02max can be translated to percent efforts as follows:
- efforts of 50% to 60% of V02max are probably equivalent to subjective feelings that the effort is 30% to 40% of maximum
- efforts of 70% to 90% of V02max are probably equivalent to subjective feelings that the effort is 60% to 80% of maximum
- efforts of 100% of V02max are probably equivalent to subjective feelings that the effort is 80% to 90% of maximum
- efforts of 90% to 100% of maximum are probably equivalent to values that are between 110% and 130% of V02max
The distance of swimming repeats has a considerable effect on these crude estimates. During short repeats the athlete may sense a lower percentage of maximum effort than the actual percentage of V02max at which he or she is swimming because the duration of the swimming will not cause intense fatigue. Subjective feelings of percent effort will correspond more closely to the percentage of V02max indicated earlier when the repeats are longer.
Heart rates, if counted correctly and interpreted properly, can provide a more accurate method than subjective percentages of maximum effort for estimating the percentage of V02max during work.
V02Max and Performance
Although a person can improve V02max by training, research shows that heredity sets limits on the amount of improvement. Generally, athletes can improve their absolute maximum oxygen consumption by 15 to 20%.
For many years, the capacity to consume oxygen maximally was considered the most valid measure of an athlete’s ability to perform in endurance events. It was believed that a large V02max would provide an athlete with a distinct advantage in endurance events and, for that reason, endurance training emphasized improving this measure. However, persons who are able to consume large quantities of oxygen during races do not always defeat those with smaller maximum consumption rates. Other factors are involved.
Percentage Utilization of V02max
More predictive of performance in endurance events is fractional percentage of maximum oxygen consumption (%v V02max). It refers to the highest rate of work that a person can perform for a long period, say 20 to 40 minutes, without becoming fatigued. It is determined by measuring an athlete’s oxygen consumption during a maximum effort swim of 20 to 40 minutes and then determining what fraction of the athlete’s maximum oxygen consumption rate it represents. For example, let us assume an athlete has the ability to consume oxygen at a maximum rate of 70ml/kg/min. If the highest rate of oxygen consumption that the person can maintain for a long time with becoming fatigued is 60ml/kg/min, then the person is able to work at 85% of V02max.
As with V02max, heredity seems to play a role in determining the highest percentage of maximum that athletes can reach (about 20% trainable). A more common term used to identify the highest fractional utilization of V02max that can be maintained for a long period is anaerobic threshold. The anaerobic threshold does not indicate the rate of work at which anaerobic metabolism begins. It represents a manageable level of anaerobic metabolism that a person can sustain for a long period without experiencing severe fatigue.
Advantages of Increasing %VO2Max
Most athletes can only maintain speeds that require them to consume oxygen maximally for 1 to 3 minutes of continuous effort before they are forced to slow their pace because of fatigue. In long races and long training sets, athletes must select speeds that require less than a maximum rate of oxygen consumption so that they do not accumulate too much lactic acid in their muscles too early. For example, most runners can complete a marathon at an average pace that requires them to use 75% to 80% of their maximal oxygen consumption capacity. You should be able to understand now why the ability to use a larger fraction of V02max in these races would be a decided advantage. Athletes who can train themselves to use 85% to 90% of V02max without becoming fatigued should be able to run their long races at a faster average pace.
The ability to compete at a higher percentage of V02max should also be advantageous in shorter events. In middle distance and distance swimming races, the pace at which athletes must compete always exceeds the pace that would produce maximum oxygen consumption. Let us assume that two athletes with identical maximum oxygen consumption ability are swimming a race that requires each of them to work at a rate equivalent to 130% of V02max. Let’s assume also that one athlete is able to work at 85%of V02max without becoming fatigued whereas the other can work at only 80% of V02max without becoming fatigued. It should be easy to see that the athlete who can swim closer to 100% of V02max will be producing less lactic acid at race pace and should therefore be able to maintain that pace longer.
Athletes with a smaller V02max can sometimes excel over competitors who have larger values through their ability to compete at a higher percentage of maximum. For example, Alberto Salazar, former world record holder in the marathon, had a V02max of 70ml/kg/min, which was lower than that of many of his competitors. But he was able to run the marathon at a pace that used 86% of his maximum, a much higher percentage utilization of V02max.